Recently, a wide variety of flame resisting synthetic resin compositions have been developed with the purpose of ensuring the safety against a fire. Among them, flame resisting synthetic resin compositions not containing halogen, phosphorus or antimony trioxide, i.e., so-called non-toxic flame resisting synthetic resin compositions of a halogen-free type are given special attention.
Generally, such a flame resisting synthetic resin composition of a halogen-free type contains an inorganic filler such as aluminum hydroxide or magnesium hydroxide. Further, the amount of the inorganic filler required to obtain sufficiently high flame resisting effect is generally 30 to 70% by weight based on the composition. However, a synthetic resin composition containing an inorganic filler in such a high content does not generally exhibit well-balanced strength, so that it is brittle and poor in processability.
Further, some synthetic resin compositions containing such a flame resistant filler alone do not exhibit sufficient flame resistance. Thus the simultaneous addition of such a filler and carbon black has been attempted with the purpose of overcoming these problems (see Japanese Patent Publication No. 10898/1982). The simultaneous addition thereof is known to impart high flame resistance to a synthetic resin, even when the amount of a flame resistant filler is relatively small. However, the halogen-free flame resisting compositions thus prepared are all black, so that they can not be applied to the fields wherein color discrimination is necessitated or the fields wherein importance is attached to appearance, i.e., the fields wherein the use of a black material is unfavorable (for example, wall covering material).